Process of manufacturing crucible compounds.



. an snares PATENT enr ch,

cant-casein, or s'ru'rroaar, GERMANY. r'nosn'ss or rasmmac'runn e cnoommbomrovnne.

reassess. p s eeten of Letters Patent. j Patented Apra 2e, ices.

Application filed January 6 1908., Serial No. #139,566.

-' Z whom it may concern: magnesia or lime orxthe like, ma be added,

it known that ,1, CanLlGAsPAR, a" all'as chemicallyf nice as possib e. I c on of the German Empire, residingat 'No single one o the ordinary and existing, Eitnttgart, Wiirtemberg, German have iii-i forms ofv A1 0 is available for the semenvented certain new and use'fu lmpr'ove "jects, butisuchmust be re aredin if'new g ments in Processes of lllanufacturingCrwand ex ensive way, whidli iiowever is stillcible fiompounds; andl do hereby'declanje the rprefera le for theseavaluable crucibles,-buticllowing to be a full, clear, and exact de- 18 much too 'dear for all other commoner, soription of the invention, such as will en- 'fireproof. productssuch as bricks, molded 1o able skilled in the art to which it apblocks, stove linin s, and the like. Calcined pertains to make and use the samez bauxite, preferab y consisting of Al 0 is Whenrei'ractory metals are to be meltedin too impure and much'too hard, so tiat it. crucibles with high and very'thin walls at very greatly affects the ca ability of the' high tern eratures, which metals must 'mater al to be easilymoldeg and its ca a 15 not absorb. carbon and silicon from the walls bility of protecting the bindin clay. he

ofthesevessels,andwhichare tobepurifiedby" two latter defects are possessed-by natural highly basic fluxes, these walls must not only and artificial corundunfi and crystalline cs so from carbon and deleterious constitu Al O .two chemical actually non suscep but must also be of a basic nature. tible,substances, toa still greater extent. Jrder however to easily form the hi h The pure amorphous finally can] '11 walls and to make perfect vesse s, only be rendered incandescent. so' far as sufmust be ossible to give to the basic subfice's for the already mentionedffireproof, -ce emp oyed therefor, the mechanical coarser products, but not so far'that its props perties of potters clay. This is only poserty of again chemicall conibinin with go ale '1" it already contains in a dried pulwater, is entirely lost. t-an'incan. escen'ti,

' n condition 'a considerable quantity heat this pulverulent body is so disintegrated y fireproof, greasy, binding clay thorby .the escaping/vapor and thereby renmixed with it, so that when worked dered so poor a conductor oi heat, that heat-. 1-

h a certain quantity of water, it asing to a higher temperaturelis much too 35 1 an easily molded and very ductile costly and inconvenient; Atthigh tem era condition. This fireproof binding tureshowever the last remains of the c emclay however consists principally of silicic ically combined water escaping as-hot, hi h acid, which, in this way, enters the basic pressurepsteam would not onlyvery'seriousy material of the vessel walls. At thejhigh damagethe Walls of the crucibles,-but by smelting heat it is attacked by the basic conits decomposition in the fluid metal, would stituents of this material itself and also. those roduce dangerous and deleterious reactions of the additions, and the molten or melting etween the water and the silicon, by which metals may react on their silicon contents. silicon would be introduced intp the metal I the other hand it and the binding clay which might make this latter brittleowing must be protected. This can only bedone to the 'oxid. All these drawbacks are onthe most complete manner possible, by tirely removed by'the following improved n one of the delicate pure powder of ure method of heating. By the addition of ohous aluminium oxid A1 0 whic alwater, rounded pieces of half-fist size, are n the proportion of 76 equivalents to formed from pure amorphous hydrate of 0 .ivalents of powdered alumina forms alumina A1 0, which dry Well and thereby: fireproof, easily nioldable or ducbecome solid and conductors of heat, and in bstanoe of slightly basic character, consequence of the added waterbeing drawn 1 urned at aninoanr escent heat becomes off remainso porous, that even at a hi h tern-w hard. This is then either treated perature aliithe chemically'coinbine water 5 or, in order to make it highly basic, can easily escape, With thesedried ieces e is mixed with it for instance 26% of suitable crucibles are entirely filled an then clay with 24% aluminium oxid and radually heated in suitable furnaces to an. pure calcinedimagnesite which is more intense, white heat, approximating to 1600 *sely powderm' than the'two other sub- (3. and left therein for a out 11} hours. They 1o noes which are alniost asi fine as flour. are then allowed to cool, closed, in order to According to circumstances, dolomite or prevent access of air, then discharged and I passed through a sieve offrom 1 1% millialumina by the addition of water, drying and 10 meters mesh after which the powder isready for use.

'I declare that what I claim is 1. The described process of manufacturing crucible compounds, consisting 'shap small pieces of pure, amorphous, hydrate =9 then heating gradually in a closedFVeShelup to an intense white heat, and theri cooling.

2. The described process of manufacturing crucible compounds, consisting iii. shaping small pieces of pure, amorphous, hydrate-of alumina b the addition o'fwater, drying and then heatm'g gradually in a'closed vessel up to an intense white heat, andmaintaining at thistemperature for a definite period, then coolin without access of air.

3. 'l he improved process for manufacturing crucible compounds which consists in sha. ing small pieces of pure, amorphous, h rate of alumina, and pure ma nesia by t e addition of water, dryin and t en heat ing in a closed vessel, grafually to intense white heat, maintaining such temperature for a' definite period, then cooling without access of air. I

' In testimony whereof I affix my signature, in presence of two witnesses.

CARL CASPAR. Witnesses:

JEAN GULDEN, HERM. HOPPE. 

